Although opinions seem to vary, here are a few less gloomy quotes from
NASA:
...during reversal the magnetic field does not go away, it only gets weaker and develops several more magnetic poles, at unpredictable locations.
...Even today, the magnetic shield is not effective near the magnetic poles, yet the radiation received there on the ground is only slightly higher than anywhere else. The reason is that our main shield against such particles is not the magnetic field of the Earth but the atmosphere, equivalent to some 10 feet of concrete.
...reversing between 1000 and 2000 years from now. It might happen, although the trend may well change.
So we should be OK then
